can anyone help tell me what the domain of this function is please
f(x) = 1
_________
sqr root of (1-x)(7+x)
What makes f(x) undefined. ie What make the denominator 0, or what makes the radical undefined (negative)
The domain is all values of x for which the function is defined.
I'll give u one place that it's not defined.........
x<-7
here's another
x>1
here's another
x=1
here's another
x=-7
So are you familiar with interval notation?
$\displaystyle (-7,1)$
A square bracket means that the endpoint is included. A round bracket means that the endpoint is not included. So a slight correction to this answer is required: (-7, 1).
@OP: Since $\displaystyle (1 - x)(7 + x) > 0$ is required, the interval is most easily found by drawing a graph of the parabola $\displaystyle y = (1 - x)(7 + x)$ and looking for the values of x such that y > 0.